** DISPUTED ** ldd in the GNU C Library (aka glibc or libc6) 2.13 and earlier allows local users to gain privileges via a Trojan horse executable file linked with a modified loader that omits certain LD_TRACE_LOADED_OBJECTS checks. NOTE: the GNU C Library vendor states "This is just nonsense. There are a gazillion other ways to introduce code if people are downloading arbitrary binaries and install them in appropriate directories or set LD_LIBRARY_PATH etc."
http://openwall.com/lists/oss-security/2011/03/07/10
http://openwall.com/lists/oss-security/2011/03/07/13
http://openwall.com/lists/oss-security/2011/03/07/7
http://openwall.com/lists/oss-security/2011/03/08/1
http://openwall.com/lists/oss-security/2011/03/08/10
http://openwall.com/lists/oss-security/2011/03/08/2
http://openwall.com/lists/oss-security/2011/03/08/3
http://openwall.com/lists/oss-security/2011/03/08/7
http://reverse.lostrealm.com/protect/ldd.html
http://www.catonmat.net/blog/ldd-arbitrary-code-execution/
http://www.redhat.com/support/errata/RHSA-2011-1526.html